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RATE OF GROWTH OF SOME SEA FISHES 

 Rhombus laevis, the Brill. 



The young brill occur floating at the surface in May and June, 

 at which stage they are in process of metamorphosis, swimming in 

 a slanting or horizontal position, and provided with a large air 

 bladder. They cannot well be less than three weeks old at this 

 stage, and the eggs must, therefore, be shed in April and May. 

 Raffaele believes that at Naples the eggs are shed in February and 

 March, and one would naturally expect the spawning period to be 

 earlier in the Mediterranean. 



According to the results observed in the specimens reared in 

 captivity, the growth would seem to be very slow, not exceeding 

 4 inches in twelve months ; but it will be seen from the table 

 that this length was almost reached in six months, so that scarcely 

 any increase in size took place after the first six months. It is 

 probable, therefore, that the growth of my captive specimens was 

 abnormally checked. In nature, these fish feed chiefly on living 

 fish of other species, and I was unable to provide such food for my 

 captive specimens, but fed them on marine worms. On the other 

 hand, I think it unlikely that the specimen obtained in the sea 

 September 30th, 1890, could have reached its length of 7*2 inches 

 in five months, and, therefore, I have considered it to be more than 

 one year old. The adult brill is from 18 inches to 2 feet long, 

 the latter being the maximum length observed. If 7 to 8 inches 

 is the average growth in one year, the growth of the brill would 

 appear to be slower in proportion to its size than that of the flounder, 

 and it would probably take four years to reach a length of 18 inches. 

 Additional data are needed, but I have found it difficult to find 

 specimens of two to twelve months old in the sea. The species is 

 much less common than the plaice, flounder, or dab, and even the 

 adults are only taken sparingly by the professional trawlers. 



